Figure 1. HBCs possess primary cilia. Immunofluorescence staining was performed on tissue from the olfactory epithelium of 3- to 6-week-old wild-type, Arl13b-EGFPtg, and EGFP-CETN2 mice. A, p63-labeled HBCs possess ARL13B-labeled cilia (inset, magnified image). Scale bars, 10 μm. B, Cilia extend from γ-tubulin-labeled basal bodies (arrows). Low-magnification view (left) and high-magnification view (right) of ciliated HBC. Scale bars, 5 μm. C, In Arl13b-EGFPtg mice, K5-labeled HBCs possess GFP+ cilia (inset, magnified image). Scale bars, 10 μm. D, HBC cilia labeled with canonical cilia markers AC3 and ARL13B (arrowheads). E, In Arl13b-EGFPtg mice, AC3 labels GFP+ cilia (arrowheads). F, p63-labled HBCs possess AC3-labeled cilia. G, In EGFP-CETN2 mice, GFP-expressing basal bodies possess AC3+ cilia (arrowheads). H, In Arl13b-EGFPtg mice, GFP+ cilia (arrows) project from p63-labeled HBCs into the interstitial space between HBCs and K18-labeled SUS cell end feet (inset, magnified image). Scale bars, 5 μm. I, In wild-type mice intranasally infected with adenovirus containing GFP, K5-labeled HBCs possess ARL13B-labeled cilia (see arrow) that project into the interstitial space between an HBC and GFP+ end foot of a SUS cell (see inset for higher magnified image). Scale bar, 10 μm. N = 10 total mice for all immunostaining. Dashed lines, Basement membrane.